I have started getting this numb tingling area about the size of a quarter on the lower right of the right knee cap. I am fairly active, but have no other pain or discomfort with this knee. I do have some lower back issues, but no other leg problems as a result of the lower back. Any ideas on what sort of things could cause this?

There is a possibility that it could relate to your lumbar spine problems. Usually when a spinal nerve is irritated or compressed, it tends to cover a larger area, like radiating down the front of the thigh and over the kneecap...but on occasion, a small patch will go numb.